A display device is often produced to include a glass substrate. The glass substrate is heavy and is easily broken when being subjected to an impact. Recently, a so-called flexible display device including a flexible substrate formed of, for example, a resin, which is lightweight and is not easily broken, is a target of attention. The flexible display device is required to be durable against bending. For example, Japanese Patent No. 5791673 discloses a display device that is improved in the durability against repeated bending and is bendable at a larger angle.